From: Stefan Nuernberger <snu@xxxxxxxxxx> Date: Mon, 17 Sep 2018 19:46:53 +0200 > commit 40413955ee26 ("Cipso: cipso_v4_optptr enter infinite loop") fixed > a possible infinite loop in the IP option parsing of CIPSO. The fix > assumes that ip_options_compile filtered out all zero length options and > that no other one-byte options beside IPOPT_END and IPOPT_NOOP exist. > While this assumption currently holds true, add explicit checks for zero > length and invalid length options to be safe for the future. Even though > ip_options_compile should have validated the options, the introduction of > new one-byte options can still confuse this code without the additional > checks. > > Signed-off-by: Stefan Nuernberger <snu@xxxxxxxxxx> Applied to net-next. This is not 'net' nor -stable material. I'm hesitent about this change as-is, and ip_options_compile() is not changing semantics in -stable in the way that you say can cause problems.